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Local monodromy of p-divisible groups

Jeff Achter·Peter Norman
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Abstract

A $p$-divisible group over a field $K$ admits a slope decomposition; associated to each slope $\lambda$ is an integer $m$ and a representation $\gal(K) \ra \gl_m(D_\lambda)$, where $D_\lambda$ is the $\rat_p$-division algebra with Brauer invariant $[\lambda]$. We call $m$ the multiplicity of $\lambda$ in the $p$-divisible group. Let $G_0$ be a $p$-divisible group over a field $k$. Suppose that $\lambda$ is not a slope of $G_0$, but that there exists a deformation of $G$ in which $\lambda$ appears with multiplicity one. Assume that $\lambda\not= (s-1)/s$ for any natural number $s>1$. We show that there exists a deformation $G/R$ of $G_0/k$ such that the representation $\gal(\Frac R) \ra \gl_1(D_\lambda)$ has large image.

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Jeff Achter, Peter Norman. 2004-02-27. Local monodromy of p-divisible groups. https://doi.org/10.1090/s0002-9947-09-04818-1

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